Four hundred years ago Galileo Galilei was the first to observe the sky with an instrument more powerful than the human eye: a telescope. His revolutionary views have changed forever our conception of the universe, laying the foundations of modern astronomy, which since then has developed a virtually unstoppable, especially in the last century. Galileo's telescope was, of course, almost rudimentary compared to the powerful tools available to contemporary astronomers, able to peer into the hidden mysteries of the cosmos and distant. But let us take a step back and put ourselves in the position of Galileo to retrace his great discoveries.
If most advanced telescopes of the time allow, in the best condition to distinguish even a car on the moon, the little telescope of 1609 had a much lower resolution: the smallest of details that allowed distinguish on the Moon, the celestial body closest to us, a hundred miles were great! Yet this resolution was sufficient for Galileo to observe the craters and mountains Moon, and demonstrate that the moon is a celestial body incorruptible and perfect as it was believed at the time. Similarly, observing the Sun, he found dark spots on its surface, the "sunspots", which is painted surface of the Sun temporarily colder than average, an ordinary process for a star. Galileo noticed that these spots are in progress: they appear and disappear at different points. Even the Sun, then, is not perfect and immutable. A new science was born, and no experimental evidence based on indisputable dogmas.
Other objects of the first Galileo's observations were the two largest planets of the Solar System Jupiter and Saturn. Discovered four moons of Jupiter, called the "Galilean moons", which revolve around the great planet exactly like the Moon revolves around the Earth and the Earth around the Sun, confirming the Copernican view of the world. Saturn was in fact the first to see a strange structure nebula surrounding it was a few years after the Dutch astronomer Huygens to discover that these are the famous rings, a structure of dust revolving around the planet, forming a kind of disc.
The discovery of a very large, and have never been seen, further outer ring of Saturn, made three weeks ago by the Spitzer Space Telescope, which observes the universe through infrared light, reminds us that even four centuries after the first observations of this planet, there is still much to discover: it is never too late to be amazed by the cosmos.
With this approach in mind, last weekend all over the world have been celebrating the Galilean Nights, a global event and an integral part of the 'International Year del'Astronomia . To discover the universe and learn to look with new tools, with new eyes, more than a thousand events have offered the public an opportunity to observe the sky, where Jupiter, Saturn and the Moon were all particularly clearly visible.
In Campania, the Science Centre of the Fondazione IDIS-Città della Scienza, Naples , opened the door for a weekend is dedicated to Galileo to Darwin , of \u200b\u200bwhose birth falls this year the two-hundredth anniversary, while in Acerno, in the province of Salerno, the Scientific-Cultural Association has organized a hemispheres Star Party with the observation of so-called "Galilean objects" in the beautiful setting Picentini.
CLAUDIA MIGNONE
the picture (NASA), an artistic representation of the new, giant ring discovered around Saturn with the Spitzer Space Telescope . The ring starts at about 6 million km from the planet, and extends for more than 12 million km.
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